Pregnancy-induced hypertension, antihypertensive drugs and the development of fetal behavioural states

In 21 pregnancies complicated by pregnancy-induced hypertension (PIH) which was treated by antihypertensive drugs (labetalol, nifedipine), fetal behavioural recordings (quiet state, CIF; active state, C2F; no coincidence, NOC) and Doppler measurements of blood flow velocity in the umbilical artery (UA) (resistance index, RI) were made on two occasions (27-32 and 33-36 weeks of gestation). Data were compared to those of a control group of normally grown fetuses (n = 96); in 15 cases we were able to match fetuses from the study group for age (± 1 week) and weight (± 150 g) at birth with fetales from a control group. It was the aim of this study to investigate if there are disturbances in the development of fetal behavioural states and if possible disturbances are due to poor fetal growth or to antihypertensive therapy. Our results show that in PIH treated by antihypertensive drugs, there are disturbances in the development of fetal behavioural states with higher percentages of NOC and C1F, lower percentages of C2F, and higher UA RI values. These disturbances are mainly due to coexisting placental impairment and poor fetal growth rather than to nifedipine or labetalol therapy, although these drugs may cause some redistribution of states.